1. Field of the Invention
The present invention relates to a liquid crystal display device and particularly to a technique for reducing the physical size of a set and enhancing the reliability of a connection portion with an external circuit.
2. Description of Related Arts
The liquid crystal display devices have been faced with a strong demand to reduce the physical size of the unit while maintaining the same screen size. This demand is particularly strong in display devices, such as liquid crystal display device for use in cellular telephones, in which the reduction of the physical size of the unit is desired.
FIG. 20 shows a structure of a module used in a conventional compact liquid crystal display device. FIG. 20A is a plan view of the module; FIG. 20B is a side view thereof; and FIG. 20C is a side view thereof as seen in the other direction. A liquid crystal display panel comprises a TFT substrate 1 and a color filter substrate 2 which are disposed in opposing relation. The TFT substrate 1 is constructed such that pixel electrodes and TFTs (thin film transistor) as switching elements corresponding thereto are arranged in a matrix form. The color filter substrate 2 is formed with a color filter for color image formation. Liquid crystal is sandwiched between the TFT substrate 1 and the color filter substrate 2, and an image is formed by controlling light from a backlight. The control of light through liquid crystal requires the light to be polarized. Hence, an unillustrated lower polarizer is affixed to a lower side of the TFT substrate 1 whereas an upper polarizer 11 is affixed to an upper side of the color filter. The TFT substrate 1, the color filter substrate 2, the unillustrated lower polarizer and the upper polarizer 11 constitute the liquid crystal display panel.
FIG. 20A is a plan view showing an arrangement wherein the liquid crystal display panel, which is provided with a driving IC chip 4, a flexible wiring substrate 5 connected with an external power source or the like and the backlight, is installed in a mold 6. Referring to FIG. 20A, the driving IC chip 4 and the flexible wiring substrate 5 are mounted to the TFT substrate 1 and hence, the TFT substrate 1 has a larger size than that of the color filter substrate accordingly. The color filter substrate 2 has the upper polarizer 11 affixed to the upper side thereof. The liquid crystal display panel having the driving IC chip 4, the flexible wiring substrate 5 and the like mounted thereto is installed in the mold 6.
The flexible wiring substrate 5 is so elongated as to occupy a substantial space. Therefore, the flexible wiring substrate is bent over one side of the mold 6 to extend to a back side of the mold 6 so that the display device may be made compact. FIG. 20B and FIG. 20C show how the flexible wiring substrate is bent. Referring to FIG. 20C, the backlight is disposed in the mold 6 at place beneath the liquid crystal display panel for applying light through the back side of the liquid crystal display panel. The aforementioned subassembly wherein the liquid crystal display panel and the like are installed in the mold 6 is housed in a frame 7. The frame 7 is normally formed from a metal. Such a constitution is disclosed in, for example, Japanese Patent Laid-Open No. 338497/2005 (Patent Document 1).